In order to assess patient condition, caregivers often desire knowledge of multiple physiological parameters of the patient. These physiological parameters include, for example, oxygen saturation (SpO2), hemoglobin (Hb), blood pressure (BP), pulse rate (PR), perfusion index (PI), and Pleth Variable Index (PVI), among others. This monitoring is important to a wide range of medical applications. Oximetry is one of the techniques that has developed to accomplish the monitoring of some of these physiological characteristics. It was developed to study and to measure, among other things, the oxygen status of blood. Pulse oximetry—a noninvasive, widely accepted form of oximetry—relies on a sensor attached externally to a patient to output signals indicative of various physiological parameters, such as a patient's constituents or analytes, including, for example, those listed above as well as a percent value for carbon monoxide saturation (HbCO), methemoglobin saturation (HbMet), fractional saturations, total hematocrit, billirubins, or the like. As such a pulse oximeter is one of a variety of patient monitors that help provide monitoring of a patient's physiological characteristics.
A pulse oximeter sensor generally includes one or more energy emission devices, such as specific wavelength emitting LEDs, and one or more energy detection devices. The sensor is generally attached to a measurement site such as a patient's finger, toe, ear, ankle, or the like. An attachment mechanism positions the emitters and detector proximal to the measurement site such that the emitters project energy into the tissue, blood vessels, and capillaries of the measurement site, which in turn attenuate the energy. The detector then detects that attenuated energy. The detector communicates at least one signal indicative of the detected attenuated energy to a signal processing device such as an oximeter, generally through cabling attaching the sensor to the oximeter. The oximeter generally calculates, among other things, one or more physiological parameters of the measurement site.
Pulse oximeters are available from Masimo Corporation (“Masimo”) of Irvine, Calif. Moreover, some exemplary portable and other oximeters are disclosed in at least U.S. Pat. Nos. 6,770,028, 6,658,276, 6,157,850, 6,002,952, and 5,769,785, which are owned by Masimo, and are incorporated by reference herein. Such oximeters have gained rapid acceptance in a wide variety of medical applications, including surgical wards, intensive care and neonatal units, general wards, home care, physical training, and virtually all types of monitoring scenarios.
Typically, the physiological parameters are displayed to the caregiver as separate numbers on a patient monitor. Although this provides a large amount of data in a relatively small space, the greater the number of parameters being monitored, the more confusing and cluttered a display can become.